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Ni-rich layered oxides, like LiNi0.8Co0.1Mn0.1O2 (NCM811), have been widely investigated as cathodes due to their high energy density. However, gradual structural transformation during cycling can lead to capacity degradation and potential decay of cathode materials. Herein, we doped high-valence transition metal (TM) ions (V5+, Nb5+, and Zr4+) at the Ni site of NCM811 by first principles simulations and explored the mechanism of doping TMs in NCMs for enhancing the electrochemical performance. Analysis of the calculations shows that doping V, Nb and Zr has an efficient influence on alleviating the Ni oxidation, reducing the loss of oxygen, and facilitating Li+ migration. Moreover, V doping can further suppress the lattice distortion due to the radius of V5+ being close to the radius of Mn4+. In particular, compared with the barrier of the pristine NCM in Li divacancy, the barrier of V-doped NCM reaches the lowest. In conclusion, V is the most favorable dopant for NCM811 to improve the electrochemical properties and achieve both high capacity and cycling stability. [ABSTRACT FROM AUTHOR]

Based on first-principle calculations, we proposed a one two-dimensional (2D) blue AsP (b-AsP) monolayer as an ideal anode material for lithium/sodium-ion (Li/Na-ion) batteries for the first time. The b-AsP monolayer possesses thermal and dynamic stabilities. The system undergoes the transition from semiconductor to metal after Li/Na atoms are embedded, which ensures good electric transportation. Most remarkably, our results indicate that the b-AsP monolayer exhibits high theoretical capacities of 1011.2 mA h g−1 (for Li) and 1769.6 mA h g−1 (for Na), low average open circuit voltages of 0.17 eV for Li4AsP and 0.14 eV for Na7AsP systems and ultrafast diffusivity with the low energy barriers of 0.17/0.15 eV and 0.08/0.07 eV of the P/As sides for Li and Na, respectively. Given these exceptional properties, the synthesis of a buckled b-AsP monolayer is desired to achieve a promising electrode material for Li- and Na-ion batteries. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations have been performed to explore the gas-phase hydrolysis reaction of mononuclear thorium halide clusters ThX4 (X = F, Cl). We have found that the hydrolysis of ThCl4 is easier than that of ThF4. Furthermore, their hydrolysis reactions favor pathways of direct dehydration of Th(OH)4 instead of further hydrolysis of ThOX2. There are some differences between the hydrolysis of ThCl4 and that of MCl4 (M = Ti, Zr and Hf). The X–H…Y (X = F, Cl; Y = F, Cl and OH) hydrogen bonds play an important role in the hydrogen transfer process of the hydrolysis reaction. The differences in the steric effects and bonding may be important factors that are related to the disparities in the hydrolysis of the above-mentioned metal halides. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) calculations are employed to investigate the reactivity of tungsten oxide clusters towards carbon monoxide. Extensive structural searches show that all the ground-state structures of (WO3)n+ (n = 1–4) contain an oxygen radical center with a lengthened W–O bond which is highly active in the oxidation of carbon monoxide. Energy profiles are calculated to determine the reaction mechanisms and evaluate the effect of cluster sizes. The monomer WO3+ has the highest reactivity among the stoichiometric clusters of different sizes (WO3)n+ (n = 1–4). The reaction mechanisms for CO with mono-nuclear stoichiometric tungsten oxide clusters with different charges (WO3−/0/+) are also studied to clarify the influence of charge states. Our calculated results show that the ability to oxidize CO gets weaker from WO3+ to WO3− as the negative charge accumulates progressively. [ABSTRACT FROM AUTHOR]

Based on first-principle electronic structure calculations and Boltzmann transport theory, we investigate the composition-dependent thermoelectric properties of germanium/silicon core/shell [110]-oriented nanowires, as well as the surface passivation effects. The results demonstrate that the ZT values depend on the surface structure and the Ge/Si ratio. Significantly, for n-type [110]-Ge/Si core/shell NWs (about 2.6 nm in diameter) ZT = 0.65 at 300 K can be obtained, that is 65 times that of bulk Si, and 1.8 times that of SiNW without the core/shell structure at the same temperature. [ABSTRACT FROM AUTHOR]

Ni-rich layered oxides, like LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811), have been widely investigated as cathodes due to their high energy density. However, gradual structural transformation during cycling can lead to capacity degradation and potential decay of cathode materials. Herein, we doped high-valence transition metal (TM) ions (V 5+ , Nb 5+ , and Zr 4+ ) at the Ni site of NCM811 by first principles simulations and explored the mechanism of doping TMs in NCMs for enhancing the electrochemical performance. Analysis of the calculations shows that doping V, Nb and Zr has an efficient influence on alleviating the Ni oxidation, reducing the loss of oxygen, and facilitating Li + migration. Moreover, V doping can further suppress the lattice distortion due to the radius of V 5+ being close to the radius of Mn 4+ . In particular, compared with the barrier of the pristine NCM in Li divacancy, the barrier of V-doped NCM reaches the lowest. In conclusion, V is the most favorable dopant for NCM811 to improve the electrochemical properties and achieve both high capacity and cycling stability.

Density functional theory (DFT) calculations have been performed to explore the gas-phase hydrolysis reaction of mononuclear thorium halide clusters ThX4 (X = F, Cl). We have found that the hydrolysis of ThCl4 is easier than that of ThF4. Furthermore, their hydrolysis reactions favor pathways of direct dehydration of Th(OH)4 instead of further hydrolysis of ThOX2. There are some differences between the hydrolysis of ThCl4 and that of MCl4 (M = Ti, Zr and Hf). The X-HY (X = F, Cl; Y = F, Cl and OH) hydrogen bonds play an important role in the hydrogen transfer process of the hydrolysis reaction. The differences in the steric effects and bonding may be important factors that are related to the disparities in the hydrolysis of the above-mentioned metal halides.

Ligand-originated isomers have been introduced into metal-organic materials to yield two complexes with almost the same coordination linkage and packing geometries but different charge-distributions, which exhibit distinct photoresponsive behaviors in the solid state.